Vehicle seat, a skin material for a vehicle seat and a method of manufacturing the vehicle seat

ABSTRACT

The vehicle seat of the invention includes a cushioning material having a ridge surrounding and defining a seating area on the cushioning material and a skin material covering the cushioning material. The skin material and cushioning material are bonded together only within the seating area. The skin material is a laminate including, in succession, a PVC layer, a knitted fabric and a closed-cell synthetic resin foam. A water proof film may be interposed between the cushioning material and the skin material outside of the seating area.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention concerns a vehicle seat and, particularly,it relates to a vehicle seat used in outdoors and a method ofmanufacturing a vehicle seat, which has good finishing, high physicalproperties, durability and weather proofness and can be manufacturedefficiently, as well as a skin material for the vehicle seat and amethod of manufacturing the vehicle seat.

[0003] 2. Statement of the Relates Art

[0004] A vehicle seat has been formed, for example, by disposing acushioning material on a bottom plate and covering them with a skinmaterial. For the vehicle seat, a seat of a concave/convex shape hasbeen proposed particularly in view of aesthetic design or convertiblefeeding upon riding. For example, a method of using a tack lasttechnique for forming the concave/convex portion or a method of coveringa cushioning material with a skin material by stitching has been knownfor the method of manufacturing the seat of the concave/convex shape.

[0005] In the tack last method, as shown in FIG. 10, a concave line isformed to a cushioning material 120 and a skin material 110 is tacklasted by a tack last means (tack last string) 140 to a bottom plate130.

[0006] The tack last seat described above involves a problem that adistinct feeling for the concave/convex shape can not be obtained whenthe concave line forms a complicate curve (such as an S-shaped curve) ora three dimensional curve, unless many tack last points are set on everyturning point of the curve.

[0007] If the number of tack last points is increased in order toovercome this drawback, a dimple-like state appears locally to the outersurface (only in the tack last points) to deteriorate the appearance, aswell as worsen the efficiency of the assembling operation. Further,since the tack last portions undergo concentrated force, the skinmaterial and the tack last means are sometimes detached.

[0008] The method of covering a cushioning member 120 with a skinmaterial 110 having the concave/convex shape formed by stitchinginvolves a drawback that undesirable separation is caused between theskin material 120 and the cushioning material 120 at the concave/convexportion, particularly, at the concave portion.

[0009] In order to solve the foregoing problem, a vehicle seat formed bycoating an adhesive on the seating area of the cushioning material andbonding the skin material thereto has been known. In this vehicle seat,an adhesive is coated at predetermined portions including ridges of thecushioning material.

[0010] However, when a rider sits on the seat, since a load exerts mostconcentrically on the ridges of the cushioning material, and, if theskin material is secured at the ridges to the cushioning material,excessive force exerts on the skin material to undesirably flex orcrease the seat.

[0011] Further, in the method of covering the cushioning material 120with the skin material 110, it is necessary to prevent water or dustsfrom intruding into the cushioning material 120 through joined portionsof a plurality of skin materials 110 stitched to each other. For thispurpose, a water proof film (not illustrated) is disposed between theskin material 110 and the cushioning material 120 at the stitchedportions of the skin material 110 to prevent intrusion of rain water orthe like by the water proof film.

[0012] In the method of using the water proof film described above, itis necessary to dispose the water proof film accurately for enabling toprevent water or dusts from intruding through the joined portions bysituating the water proof film at appropriate positions.

[0013] Further, in a vehicle seat formed by covering the cushioningmaterial 120 with the skin material 110 by stitching, since separationtends to be caused between the skin material 110 and cushioning material120 at concave/convex portions, particularly, at concave portions, amethod of coating an adhesive between the skin material 110 and thecushioning material 120 to prevent separation has been known.

[0014] When the adhesive is coated between the skin material 110 and thecushioning material 120, if the water proof film is not disposed at anappropriate position, the water proof film comes into an adhesivecoating region to suffer from twisting by the deposition of theadhesive, or the water proof film is put between the adhesive and theskin material 110, to interfere the adhesion between the skin material110 and the cushioning material 120.

[0015] Therefore, it is necessary to accurately cut off the water prooffilm at exact positions, but the operation conducted while confirmingthe cut off position is laborious, to result in a problem that theoperation can not be conducted efficiently.

[0016] Further, the vehicle seat is generally formed as an integralcellular molding product comprising a skin material, a cushioningmaterial and a bottom plate, for example, a polyvinyl chloride skinmaterial and a polyurethane cellular material.

[0017] As shown, for example, in FIG. 15 and FIG. 16, the vehicle seatcomprises a skin material 110 and a cushioning material 120, and theskin material 110 is constituted by applying a surface treating acrylicmaterial 111 to a synthetic resin 112 or laminating a synthetic resin112 on a substrate fabric 113 and applying a surface treating material111 on the synthetic resin 112. Then, the skin material 110 is bonded atthe surface of the synthetic resin 112 or the substrate fabric 113 usingan adhesive 140 to the cushioning material 120.

[0018] In the prior art described above, if a polyvinyl chloride skinmaterial is used, for example, as the synthetic resin 112, it results ina drawback that vinyl resin-like gloss appears on the surface to lack ina grave feeling.

[0019] Further, contact between the skin material 110 and the cushioningmaterial 120 results in the following disadvantages.

[0020] That is, a plasticizer contained in the synthetic resin 112migrates to the cushioning material 120 to deteriorate the cushioningmaterial.

[0021] Further, when a plasticizer contained in the synthetic resin 112migrates to the cushioning material 120, the amount of the plasticizercontained in the synthetic resin 112 is decreased to make the syntheticresin 112 hard and worsen the feeling upon sitting on the seat.

[0022] Further, an amine catalyst contained in the cushioning material120 gives an effect on the synthetic resin 112 to cause discoloration orfading in the synthetic resin 112, thereby deteriorating the aestheticappearance of the vehicle seat.

[0023] Further, if a solvent type adhesive is used as an adhesive 140for bonding the skin material 110 and the cushioning material 120, asolvent contained in the adhesive migrates to the synthetic resin 112 todiscolor the synthetic resin 112.

[0024] For overcoming the drawbacks described above, it has been known amethod of preventing migration of the plasticizer or the amine catalystby disposing an amide type resin film or a polyethylene type resin filmbetween the skin material and the cushioning material, but thisincreases the number of parts to make the manufacturing cost expensiveand increase the number of steps.

SUMMARY OF THE INVENTION

[0025] An object of the present invention is to provide a vehicle seatin which a water proof film is disposed accurately at stitched portionsof a skin material for covering a cushioning material and reliablypreventing water or dusts from intruding through the stitched portionsof the skin material, as well as a method of manufacturing such avehicle seat.

[0026] Another object of the present invention is to provide a vehicleseat with preferred finishing, having high durability and capable ofbeing manufactured efficiently, as well as a method of manufacturingsuch a vehicle seat.

[0027] A further object of the present invention is to provide a skinmaterial for use in a vehicle seat having a satisfactory appearance, andcapable of preventing migration of a plasticizer contained in asynthetic resin to a cushioning material without increasing the numberof parts and a number of steps, thereby preventing worsening of feelingupon sitting on a seat and degradation of the cushioning material.

[0028] A further object of the present invention is to provide a skinmaterial for use in a vehicle seat free from the worry of discolorationor fading in the skin material caused by an amine catalyst contained ina cushioning material.

[0029] A further object of the present invention is to provide a skinmaterial for use in a vehicle seat capable of preventing discolorationof a skin material caused by migration of a solvent to the skin materialwhen a solvent type adhesive is used for bonding the skin material andthe cushioning material.

[0030] A still further object of the present invention is to provide askin material for use in a vehicle seat that can be bonded by highfrequency welding.

[0031] A still further object of the present invention is to provide askin material for use in a vehicle seat having satisfactory leather-likefeeling, with no degradation due to abrupt shifting of load when a ridersits on the seat and showing high weather proofness to the weather.

[0032] In the present specification, “vehicle seat” includes those seatsfor land motorcycles or scooters, as well as snow mobiles and watermotorcycles and, further, includes vehicle seats for tricycled buggyvehicles, mounting vehicles or building machine seats.

[0033] The present invention is to be explained with reference toembodiments based on claims.

[0034] A vehicle seat S of the present invention has a constitution inwhich a cushioning material 20 is disposed on a bottom plate 30, and thecushioning material 20 is covered with a skin material 10.

[0035] The skin material 10 and the cushioning material 20 are bondedwith an adhesive 40 coated to a region 50 inward of a ridge 12 for aseating area of the cushioning material 20, excepting for the top end ofthe seat. The adhesive 40 is coated to one or both of the skin material10 and the cushioning material 20.

[0036] When the skin material and the cushioning material are bonded bythe adhesive in this way, it suitably facilitates the assemblingoperation between the cushioning material and the skin material.

[0037] Further, since the adhesive is coated to a region inward of theridge for the cushioning material, the skin material is not secured atthe ridge portion undergoing a most localized load, no excessive forceexerts on the skin material, thereby preventing occurrence of flexion orcrease, to obtain a vehicle seat of good appearance.

[0038] Further, the skin material 10 is formed by joining a skinmaterial 10 a including a seating area and a skin material 10 b notincluding the seating area.

[0039] Stitching of a plurality of skin materials in this way it ispossible to form a desired concave/convex shape.

[0040] A concave groove 22 is formed at a predetermined positionincluding a joining line 10 c for joining the skin material 10 a and theskin material 10 b, on the side of the ridge 23 of the cushioningmaterial 20 from the joining line 10 c to a region of the seating area.Then, a water proof film 21 is disposed between the skin material 10 andthe cushioning material 20 from the skin material 10 b not including theregion of the seating area to the position for the concave groove 22.

[0041] As described above, in the vehicle seat of this embodiment, sincethe concave groove is formed at a predetermined position including thejoining line on the side of the ridge of the cushioning material, fromthe joining line to the region of the seating area, the water proof filmcan be disposed simply at an appropriate position by disposing the waterproof film from the skin material not including the region of theseating area to the position for the concaved groove, with the concavegroove being as a guide line.

[0042] The skin material 10 comprises a PVC layer 12, a substrate fabric13 composed of a knitted material and a closed-cell cellular syntheticresin 14 laminated in this order, and an acrylic or vinyl chloride typesurface treating material 11 is applied to the PVC layer 12.

[0043] An acrylic or vinyl chloride type surface treating material 11 isapplied to the PVC layer 12.

[0044] As described above, since the surface treating material 11 isdisposed to the skin material 10, an embossing fabrication can beapplied to the surface treating material 11, thereby providing the seatsurface with a leather-like feeling to obtain a satisfactory vehicleseat having grave feeling in view of appearance.

[0045] When a vinyl chloride—acrylate copolymer resin or a vinylchloride—methacrylate copolymer resin is used as the surface treatingmaterial 11, a high frequency welding can be applied to secure the skinmaterials 10 with each other or secure the skin material 10 at theperipheral end thereof to the bottom plate 30 reliably and easily.

[0046] The substrate fabric 13 composed of knitted material is made ofyarns comprising at least one of nylon yarns, polyester yarns or rayonyarns.

[0047] Since the substrate fabric 13 is disposed in adjacent with thePVC layer 12, when the skin material 10 is pulled, no direct force isapplied to the closed-cell cellular material 14 to prevent breakage ofthe closed-cell cellular material 14.

[0048] Further, since the closed-cell cellular material 14 is presentbetween the PVC layer 12 constituting the skin material 10 and thecushioning material 20, the plasticizer contained in the PVC layer 12 nomore migrates through the substrate fabric 13 to the cushioning material20 thereby enabling to prevent degradation of the cushioning material20.

[0049] Further, since the closed-cell cellular material 14 is presentbetween the PVC layer 12 and the cushioning material 20, the plasticizercontained in the PVC layer 12 no more migrates through the substratefabric 13 to the cushioning material 20 thereby enabling to preventhardening of the PVC layer due the decrease of the plasticizer toprevent disadvantage that the feeling upon sitting on the seat isworsened.

[0050] Further, since the closed-cell cellular material 14 is presentbetween the PVC layer 12 and the cushioning material 20, an aminecatalyst contained in the cushioning material 20 no more migrates to thePVC layer 12 to prevent discoloration or fading in the PVC layer 12. Inthis way, it is possible to prevent the disadvantage of deterioratingthe aesthetic appearance of the vehicle seat always exposed externallyto the weather.

[0051] Further, since the cellular material 14 of the closed-cells ispresent between the PVC layer 12 and the cushioning material 20, asolvent contained in the adhesive for bonding the skin material 10 andthe cushioning material 20 no more migrates to the PVC layer 12 toprevent discoloration of the PVC layer 12.

[0052] It is suitable that the closed-cell cellular material 14 is acrosslinked cellular material and, more specifically, a PVC cellularmaterial.

[0053] Crosslinked cellular material has heat resistance and showsexcellent weather resistance when exposed to the broiling weather for along period of time.

[0054] Further, use of the PVC cellular material as the closed-cellcellular material 14 can reliably cover the cushioning material 20 ofpoor water proofness in spite of the laminate structure, therebyenabling to ensure the weather proofness of the seat. Further, this canprovide a satisfactory leather-like feeling to the skin material.

[0055] Furthermore, since lamination of the cushioning closed-cellcellular material 14 on the cushioning material 20 gives a nature ofmoderating impact shock, rider's sitting shock is moderated.Furthermore, it also provides an effect of causing less degradation byabrupt shifting of load upon sitting to obtain a high durability.

[0056] The skin material 10 may contain a protein material. With such aconstitution, it provides an effect of making the surface of the vehicleseat not sticky but giving smooth and fresh feeling. It is possible toprevent undesirable moistened feeling upon sitting, and this canfacilitate cleaning upon contamination of the seat surface. Furthermore,it also provides an effect of providing moderate gloss to the surface ofthe seat to improve the aesthetic appearance of the seat.

[0057] The method of manufacturing the vehicle seat comprises thefollowing steps.

[0058] At first, an adhesive 40 is coated to a region inward of a ridge23 for the seating area of a cushioning material 20. Further, anadhesive 40 is coated on the surface of a skin material 10 in contactwith the region inward of the ridge 23 for the seating area of thecushioning material 20.

[0059] Then, the skin material 10 and the cushioning material 20 arepress-bonded to cover the cushioning material 20 with the skin material10.

[0060] Alternatively, it may be adapted a method of vacuum forming askin material 10, coating an adhesive 40 to the region inward of theridge 23 for the seating area of the cushioning material 20 and thesurface of the skin material 10 is contact with a region inward of theridge 23 for the seating area of the cushioning material 20, then pressbonding the skin material 10 and the cushioning material 20 and coveringthe cushioning material 20 with the skin material 10.

[0061] As described above, by vacuum formation of the skin material, itis possible to cope even with the cushioning material of an abruptconcave/convex shape to ensure the freedom of the design and theperformance.

[0062] Alternatively, a concave groove 23 may be formed to a cushioningmaterial 20 on the side facing a skin material 10 at a predeterminedposition including a joining line 10 c for the skin material 10 in aregion from the joining line 10 c to the seating area.

[0063] Then, a water proof film 21 is attached to the cushioningmaterial 20. Further, the water proof film 21 is cut off along theconcaved groove 23.

[0064] Then, an adhesive 40 is coated to the surfaces of the cushioningmaterial 20 and the skin material 10 in contact with each other topress-bond the skin material 10 and the cushioning material 20. Finally,the cushioning material 20 is covered with the skin material 10.

[0065] As described above, in the method of manufacturing the vehicleseat according to the present invention, a concave groove is disposed tothe cushioning material, and the water proof film can be disposed at anappropriate position by merely cutting off the water proof film alongthe concave groove with the concave groove being as a guide line, toimprove the operation efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

[0066]FIG. 1 is a perspective view showing a vehicle seat according tothe present invention;

[0067]FIG. 2 is a cross sectional taken along line A-A in FIG. 1;

[0068]FIG. 3 is a perspective view showing a cushioning material;

[0069]FIG. 4 is a cross sectional view taken along line B-B in FIG. 3;

[0070]FIG. 5 is a cross sectional view for a main portion of a vehicleseat;

[0071]FIG. 6 is an enlarged cross sectional view for a groove portion;

[0072]FIG. 7 is an explanatory view showing a vehicle seat using avacuum formed skin material;

[0073]FIG. 8 is a cross sectional view taken along line C-C in FIG. 7;

[0074]FIG. 9 is a perspective view showing another example for the shapeof a seat for use in a motorcycle;

[0075]FIG. 10 is an explanatory view showing a prior art example;

[0076]FIG. 11 is an explanatory view showing a prior art example;

[0077]FIG. 12 is an explanatory view showing a prior art example;

[0078]FIG. 13 is an explanatory view showing a prior art example;

[0079]FIG. 14 is an explanatory view showing a prior art example;

[0080]FIG. 15 is an explanatory view showing a prior art example; and

[0081]FIG. 16 is an explanatory view showing a prior art example.

PREFERRED MODE OF PRACTICING THE INVENTION

[0082] In this embodiment, explanation is to be made to an example of amotorcycle seat S as a vehicle seat.

[0083] A motorcycle seat S of this example is a motorcycle seat in whicha cushioning material 20 is disposed on a bottom plate 30, and thecushioning material is covered with a skin material 10. That is, theseat is formed by placing a cushioning material 20 on the bottom plate30, covering the cushioning material 20 with the skin material 10, andsecuring the peripheral end of the skin material 10 at the rear face ofthe bottom plate 30.

[0084] The skin material 10 is formed conforming a sterical shape of thecushioning material 20 by stitching a skin material 10 a including aregion of a seating area and a skin material 10 b not including theregion of a seating area such that the cushioning material 20 may becovered. A joining line 10 c is defined as a joined portion between theskin material 10 a including the region of a seating area and the skinmaterial 10 b not including a region of the seating area.

[0085] Then, the constitution of the material for the skin material 10is to be explained. FIG. 2 is a cross sectional view taken along A-A inFIG. 1. The skin material 10 comprises a lamination of a PVC layer 12 onthe surface, a substrate fabric 13 and a synthetic resin closed-cellcellular synthetic resin 14. That is, the PVC layer 12 and theclosed-cell cellular material 14 are laminated with the substrate fabric13 put therebetween. As described above, closed-cell cellular material14 is present between the PVC layer 12 and the substrate fabric 13, andthe cushioning material 20. The closed-cell cellular material 14 is acrosslinked cellular material, more specifically, a PVC cellularmaterial 14 is used.

[0086] The skin material 10 is applied with a surface treating material11 and optional embossing is applied to the outside of the skin material10 to so as to provide leather-like feeling. Embossing can be applied byusing a known pressing machine or embossing machine such as a gravurepressing machine or roll embossing machine, and a concave/convex shapeof an embossing plate is formed on the seat by heat and pressure.

[0087] The surface treating material 11 in this embodiment comprises,more specifically, a vinyl chloride—acrylate copolymer resin or a vinylchloride—methacrylate copolymer resin.

[0088] As the PVC layer 12, PVC and a protein powder of 1 to 40 μm grainsize (for example, fine powder of natural protein fiber) compoundedtogether may be used.

[0089] The protein powder having a grain size of from 3 to 8 μm,preferably, 4 to 7 μm is used for ensuring uniform dispersion for thethickness of the PVC material 11 that forms the surface layer of theskin material 10.

[0090] The substrate fabric 13 in this embodiment comprises a knittedmaterial of using nylon yarns, polyester yarns, rayon yarns or likeother synthetic resin yarns.

[0091] In this embodiment, an adhesive (urethane-type) not illustratedis coated to the surfaces of the substrate fabric 13 in contact with thePVC layer 12 and the closed-cell cellular material 14 respectively, andthe substrate fabric 13 and the PVC layer 12, and the substrate fabric13 and the closed-cell cellular material are formed integrally.

[0092] In this embodiment, PVC cellular material is used as an exampleof the closed-cell cellular material but PE foams (polyethylene foams)and PP foams (polypropylene foams) may also be used in addition to thePVC cellular material. Also in this case, the material is constituted asthe closed-cell cellular material.

[0093] The PVC layer 12, the substrate fabric 13 and the closed-cellcellular material 14 that constitute the skin material 10 can belaminated not only by the method of coating the urethane type adhesiveto the substrate fabric but also by other known techniques.

[0094] For example, each of the layers can be bonded by high frequencywelder processing to each other. A predetermined fabrication line can beformed by the high frequency welder processing.

[0095] Since the skin material 10 of this embodiment is composed ofmaterials that can be bonded by high frequency welding such as thesurface treating material 11 comprising the vinyl chloride—acrylatecopolymer resin or the vinyl chloride—methacrylate copolymer resin, andthe PVC layer 12, high frequency welding can be applied easily toportions for joining a plurality of skin materials. Accordingly, it ispossible to provide the joined portions with a strength efficiently andreliably.

[0096] Then, the cushioning material 20 in this embodiment is to beexplained. The cushioning material 20 in this embodiment is made ofurethane foams. As shown in FIG. 3, a water proof film 21 is appended tothe cushioning material 20 at a position corresponding to the joinedportion of the skin material 10 in this embodiment.

[0097]FIG. 4 is a cross sectional view taken along line B-B in FIG. 3,which illustrates a cross section of the cushioning material 20 to theright of line b-b. As shown in FIG. 4 and FIG. 5, a concave groove 22 isformed on the side of an ridge 23 of the cushioning material 20, at apredetermined position including a joining line 10 c along which a skinmaterial 10 a and a skin material 10 b are joined from the joining line10 c to a region of the seating area.

[0098] Then, the water proof film 21 is disposed with the concave groove22 being as a guide line. That is, as shown in FIG. 6, the water prooffilm 21 is cut off at a position of the concave groove 22. Thus, thewater proof film 21 is disposed at an appropriate position on theseating face of the cushioning material 20 without extending to abonding face 50 between the skin material 10 and the cushioning material20 as will be described later.

[0099] In this embodiment, the shape of the concave groove 22 is shownas a substantially V-shaped cross section so that a cutting means suchas scissors can be inserted easily upon cutting off the water proof film22, but the shape of the groove is not restrictive and it may also be arectangular or substantially U-shaped cross section.

[0100] In this embodiment, when the skin material 10 is covered to thecushioning material 20, they are bonded by an adhesive 40. The adhesive40 is coated on one or both of the skin material 10 and cushioningmaterial 20 and various types of adhesive may be used.

[0101] The adhesive 40 comprises, for example, a hot melt adhesive inthe form of a adhesion film, and the hot melt adhesive includes thosecontaining active double bonds in the adhesive and hardened under theirradiation of UV-rays or electron beams, those having epoxy groups anda latent curing agent and hardened thermally, those containing NCOgroups and Si (OR)₃ groups and hardened under the presence of moistureand those containing SH groups and a metal oxide catalyst and hardenedby oxygen. Urethane type moisture curing adhesive is particularlypreferred. An actual example of the urethane type moisture curingadhesive is a moisture curing hot melt adhesive mainly comprising apolyester type isocyanate pre-polymer, and commercially availableproducts can be used therefor.

[0102] In this embodiment, a solvent type adhesive may also be used asthe adhesive 40. As described above since the closed-cell cellularmaterial 14 is disposed between the PVC layer 12 constituting the skinmaterial 10 and the cushioning material 20 in this embodiment, migrationof the solvent to the PVC layer 12 is prevented.

[0103] In the motorcycle seat S of this embodiment, as shown in FIG. 1,the skin material 10 and the cushioning material 20 are bonded within abonding range 50 which is a region inward of the ridge 23 for thecushioning material 20.

[0104] Then, explanation is to be made to the bottom plate 30.

[0105] The bottom plate 30 is molded from a synthetic resin in thisembodiment. On this bottom plate of the synthetic resin, the cushioningmaterial 20 is placed and the cushioning material 20 is covered with thesurface material 10 and the peripheral end of the skin material 10 issecured to the back of the bottom plate 30. The bottom plate 30 is madeof a synthetic resin in this embodiment, but various kinds of materialsmay be used for the bottom plate.

[0106] The peripheral end of the skin material 10 can be secured to thebottom plate 30 by securing the peripheral end of the skin material witha securing means such as staples, or by applying high frequency welding.

[0107] That is, since the skin material 10 in the present inventioncomprises materials that can be welded by high frequency welding such asthe surface treating material 11 made of a vinyl chloride—acrylatecopolymer resin or a vinyl chloride—methacrylate copolymer resin and thePVC material, high frequency welding means such as supersonic welding orradio frequency welding can be used. The treatment for the peripheralend can be applied reliably and efficiently by adopting the highfrequency welding.

[0108] In this embodiment, the explanation has been made to themotorcycle seat S as an example, so that the cushioning material 20 isplaced on the bottom plate 30, and the peripheral end of the skinmaterial is secured to the bottom plate 30. In a seat of otherconstitutions, for example, in a seat for use in building machines, thecushioning material is placed on a frame, and the peripheral end of theskin material 10 is secured to the frame.

[0109] Then, a method of manufacturing the motorcycle seat S accordingto the present invention is to be explained. At first, an adhesive forbonding the water proof film 21 is coated on the cushioning material 20,and the water proof film 21 is appended to the cushioning material 20.

[0110] In this embodiment, since the concave groove 22 is formed to thecushioning material 20, the water proof film 21 is cut off at a portionof forming the concave groove 22 with the concave groove 22 as a guideline.

[0111] Further, the adhesive is coated on the region 50 inward of theridge 23 for the seating area of the cushioning material 20. Theadhesive 40 is coated to one or both of the skin material 10 and thecushioning material 20.

[0112] Finally, the skin material 10 and the cushioning material 20 arepress-bonded to cover the cushioning material with the skin material 10,and the peripheral end of the skin material is applied with heattreatment or tack last treatment, to complete the motorcycle seat S.

[0113] In addition to the manufacturing method described above, the skinmaterial 10 may be molded to a concave/convex shape by vacuum formingand joined to the cushioning material 20. By vacuum forming the skinmaterial 10, the skin material 10 can be provided with theconcave/convex shape conveniently.

[0114] In the prior art, when a motorcycle seat S having a complicateconcave/convex shape is to be formed, a sterical configuration is formedby stitching a plurality of skin materials 110 as shown in FIG. 12 toFIG. 14 for providing the skin material 10 with the concave/convexportion conforming the seat configuration. However, when the vacuumforming is adopted, even a motorcycle seat S having a complicateconcave/convex shape, for example, as shown in FIG. 9, the skin material10 can be provided with such concave/convex shape simply conforming theseat configuration.

[0115]FIG. 7 shows a motorcycle seat S using a skin material 10 moldedby vacuum forming. FIG. 8 is a cross sectional view taken along line C-Cin FIG. 7, which shows a cross section of the motorcycle seat S left toline c-c in the figure. As shown in FIG. 8, an adhesive 40 is coated toa skin material 10 molded into a concave/convex shape by vacuum forming,and a cushioning member comprising a cushioning material 20 and a bottomplate 30 is placed under pressure in a mold frame and secured.

[0116] Alternatively, a method of coating an adhesive 40 to a skinmaterial 10 molded into a concave/convex shape in a mold frame and thencharging a starting material for urethane foams and molding the same byblowing may be used.

[0117] The vacuum formation of the skin material 10 can cope with acushioning material even if it has an abrupt concave/convex shapethereby enabling of ensure the freedom of design and high performance.

[0118] In the foregoing embodiment, the explanation has been made to asingle-seat type motorcycle seat S as a motorcycle seat S, but it may beused for a two seat type as shown in FIG. 9, and there is no particularrestriction for the shape of the seat.

[0119] Industrial Applicability

[0120] According to the present invention, the following effects can beobtained:

[0121] (1) Since the skin material and the cushioning materialconstituting the vehicle seat are bonded by the adhesive coated to theregion inward of the ridge for the seating area except for the top endof the seat, the skin material is not secured at the ridge which mostundergoes the localized load, so that no excessive force exerts on theskin material thereby preventing occurrence of flexion or creasing toobtain a vehicle seat of favorable appearance.

[0122] (2) Since the skin material is not bonded but left free from thevicinity of the ridge of the cushioning material to the peripheral end,covering to the cushioning material and assembling work such as tacklast treatment can be conducted easily to improve the operationefficiency.

[0123] (3) Since the concave groove is formed to the cushioning materialon the side facing the skin material including the seating area, at aposition spaced apart by a predetermined distance from the joining linebetween the skin material including the seating area and the skinmaterial not including the seating area along the joining line, thewater proof film can be disposed simply at an appropriate position bydisposing the water proof film from the skin material not containing theseating area to the position for the concave groove with the concavegroove being as the guide line.

[0124] (4) The skin material comprises the PVC layer, the substratefabric made of knitted material and the closed-cell cellular syntheticresin laminated successively, and surface treating material the acrylicor vinyl chloride material is applied to the PVC layer. Since thesurface treating material is applied to the skin material, the surfacetreating material can be embossed to provide a seat surface with aleather-like feeling, to obtain a satisfactory vehicle seat having agrave feeling in view of appearance.

[0125] (5) When the vinyl chloride—acrylate copolymer resin or the vinylchloride—methacrylate copolymer resin is used for the surface treatmentmaterial, high frequency welding can be applied and bonding of the skinmaterials to each other and the securing of the peripheral end of theskin material to the bottom plate can be conducted reliably and easily.

[0126] (6) Since the substrate fabric is disposed in adjacent with thePVC layer, when the skin material is pulled, the tension does notdirectly exert on the closed-cell cellular material, thereby enabling toprevent breakage of the closed-cell cellular material.

[0127] (8) Since the closed-cell cellular synthetic resin material ispresent between the PVC layer constituting the skin material and thecushioning material, migration of the plasticizer contained in the PVClayer through the substrate fabric to the cushioning material can beeliminated to prevent degradation of the cushioning material.

[0128] (9) Since the closed-cell cellular synthetic resin material ispresent between the PVC layer constituting the skin material and thecushioning material, migration of the plasticizer contained in the PVClayer through the substrate fabric to the cushioning material can beeliminated to prevent the PVC layer from hardening by the decrease ofthe plasticizer and prevent the disadvantage of worsening the feelingupon sitting on the seat.

[0129] (10) Since the closed-cell cellular synthetic resin material ispresent between the PVC layer constituting the skin material and thecushioning material, migration of the amine catalyst contained in thecushioning material to the PVC layer can be eliminated to preventdiscoloration and fading of the PVC layer. As described above, it ispossible to prevent the disadvantage of deteriorating the aestheticappearance of the vehicle seat always exposed externally to the weather.

[0130] (11) Since the closed-cell cellular synthetic resin material ispresent between the PVC layer constituting the skin material and thecushioning material, even if a solvent type adhesive is used for bondingthe skin material and the cushioning material, the solvent contained inthe adhesive does not migrate to the PVC layer, to prevent discolorationof the PVC layer.

[0131] (12) Since the crosslinked cellular material of excellent heatresistance is used for the closed-cell cellular material, it is possibleto prevent degradation of the cellular material even when it is exposedto the broiling weather for a long time.

[0132] (13) Since the PVC cellular material is used as the closed-cellcellular material, a cushioning material having poor water proofness,though being a laminate, can be covered firmly to ensure weatherproofness of the seat and provide the skin material with leather-likefeeling.

[0133] (14) Since shock-moderating property is obtained by laminatingthe cushioning closed-cell cellular material on the cushioning material,it can provide effects of moderating rider's shock upon sitting, andobtaining high durability with less deterioration caused by abruptshifting of load upon sitting.

[0134] (15) Since the protein material is contained in the skinmaterial, it provides the surface of the vehicle seat with non-tacky andsmooth and fresh feeling. Undesirable moistened feeling of the seatduring sitting is also eliminated and cleaning for the contaminated seatsurface is facilitated. An appropriate gloss can be provided to the seatsurface to improve the appearance of the seat,

What is claimed is:
 1. A vehicle seat in which a cushioning material iscovered with a skin material, wherein the skin material and thecushioning material are bonded by an adhesive coated to a region inwardof a ridge for a seating area of the cushioning material.
 2. A vehicleseat as defined in claim 1, wherein the adhesive is coated to one orboth of the skin material and the cushioning material.
 3. A vehicle seatas defined in claim 1, wherein the skin material is formed by joining askin material including a region of a seating area and a skin materialnot including the region of the seating area.
 4. A vehicle seat asdefined in claim 3, wherein a concave groove is formed to the cushioningmaterial on the side of the ridge at a predetermined position includinga joining line for joining the skin materials from the joining line tothe side of the region of the seating area, and a water proof film isdisposed between the skin material and the cushioning material from theside of the skin material not including the region of the seating areato the position for the concave groove.
 5. A skin material for use in avehicle seat in which the cushioning material is covered with the skinmaterial, wherein the skin material comprises a PVC layer, a substratefabric made of a knitted material and a closed-cell cellular syntheticresin material laminated successively.
 6. A skin material for use in avehicle seat as defined in claim 5, wherein the PVC layer is appliedwith a surface treating material made of an acrylic or vinyl chloridematerial.
 7. A skin material for use in a vehicle seat as defined inclaim 5, wherein the surface treating material comprises a vinylchloride—acrylic ester copolymer resin or a vinyl chloride—methacrylatecopolymer resin.
 8. A skin material for use in a vehicle seat as definedin claim 5, wherein the substrate fabric made of a knitted materialcomprises yarns of any one of nylon yarns, polyester yarns or rayonyarns.
 9. A skin material for use in a vehicle seat as defined in claim5, wherein the closed-cell cellular synthetic resin material is acrosslinked cellular material.
 10. A skin material for use in a vehicleseat as defined in claim 5, wherein the closed-cell cellular syntheticresin material is a PVC cellular material.
 11. A skin material for usein a vehicle seat as defined in claim 5, wherein the skin materialcontains a protein material.
 12. A skin material for use in a vehicleseat as defined in claim 5, wherein the PVC layer, the substrate fabricand the closed-cell cellular synthetic resin material are laminated andbonded by way of a urethane type adhesive.
 13. A method of manufacturinga vehicle seat in which a cushioning material is covered with a skinmaterial, wherein the method comprises; a step of coating an adhesive toat least one of a region inward of a ridge for a seating area of thecushioning material and a skin material disposed to a region inward ofthe ridge for the seating area of the cushioning material, a step ofcovering the skin material to the cushioning material, a step ofpress-bonding the skin material and the cushioning material, and a stepof applying a treatment to the peripheral end of the skin material. 14.A method of manufacturing a vehicle seat as defined in claim 13, whereinthe method comprises; a step of vacuum forming the skin material, priorto a step of coating an adhesive to at least one of the region inward ofthe ridge for the seating area of the cushioning material and the skinmaterial disposed to the region inward of the ridge for the seating areaof the cushioning material, and a step of vacuum forming the skinmaterial.
 15. A method of manufacturing a vehicle seat as defined inclaim 13, wherein the method comprises the steps of: forming the skinmaterial by joining a skin material including the region of the seatingarea and a skin material not including the region of the seating area,forming a concave groove at a predetermined position including a joiningline for joining the skin materials on the side of the ridge for thecushioning material from the joining line to a region of the seatingarea, and covering a water proof film over the cushioning material andthen cutting off the water proof film along the concave groove.